Along the line of Phys. Rev. Research 2, 023267 (2020), Phys. Rev. Research 3, 013226 (2021) and Phys. Rev. Research 3, 043176 (2021), in this work we develop the theory of symmetry defects of higher-rank continuous symmetry (HRS) in spontaneously HRS breaking phases dubbed fractonic superfluids. According to Noether's theorem, HRS is associated with the conservation law of higher moments, e.g., dipoles, quadrupoles, and angular moments. The familiar vortices in 2D conventional superfluid thin film are identified as defects of rank-0 U (1) symmetry that is associated with particle number conservation. We start with a fractonic superfluid with angular moment conservation. We establish configurations of defects. Then, we construct bound states of symmetry defects, which have finite excited energy. By using bound states, we study the physical consequence of proliferation of symmetry defects, which leads to a hierarchical structure of defect proliferation. Various scenarios of Kosterlitz-Thouless-type topological transitions driven by higher-rank defects are discussed.